How to use math symbols with ggdag

[This article was first published on Shige's Research Blog, and kindly contributed to R-bloggers]. (You can report issue about the content on this page here)
Want to share your content on R-bloggers? click here if you have a blog, or here if you don't.

The wonderful package ggdag can easily make DAG like this:

However, what we really want to include in publications is something like this:

The second one can include subscript and superscript, among many others. After some tweaking, I found a solution, not perfect but usable for now.


“`{r, echo=FALSE}
dag <- dagify(Y1 ~ X + Z1 + Z0 + U + P,
              Y0 ~ Z0 + U,
              X ~ Y0 + Z1 + Z0 + P,
              Z1 ~ Z0,
              P ~ Y0 + Z1 + Z0,
              exposure = “X”,
              outcome = “Y1”)

dag %>% 
  tidy_dagitty(layout = “auto”, seed = 12345) %>%
  arrange(name) %>% 
  ggplot(aes(x = x, y = y, xend = xend, yend = yend)) +
  geom_dag_point() +
  geom_dag_edges() +
  geom_dag_text(parse = TRUE, label = c(“P”, “U”, “X”, expression(Y[0]), expression(Y[1]), expression(Z[0]), expression(Z[1]))) +

Here the trick is to sort the tidy version of the DAG data by “name”, then we can assign labels by the order of the name of the nodes. I hope a more automated approach can be developed in the future.

By the way, with thee package latex2exp, it is straightforward to use LaTeX instead of plotmath commands.

To leave a comment for the author, please follow the link and comment on their blog: Shige's Research Blog. offers daily e-mail updates about R news and tutorials about learning R and many other topics. Click here if you're looking to post or find an R/data-science job.
Want to share your content on R-bloggers? click here if you have a blog, or here if you don't.

Never miss an update!
Subscribe to R-bloggers to receive
e-mails with the latest R posts.
(You will not see this message again.)

Click here to close (This popup will not appear again)